1. Field of the Invention
The present invention relates to a novel electrochemical method for the detection and the classification of microbial cells, especially living microbial cells. More specifically, it relates to a novel method for detecting or determining cell numbers (of living cells) or types of cells of, for example, microorganisms, animals, and plants.
2. Description of the Prior Art
The detection of the living cells of microorganisms, animals, and plants is extremely important in, for example, clinical, environmental, and bioindustrial fields. Cell numbers have been heretofore detected by, for example, turbidity methods or micrographical direct counting methods. However, it is difficult to distinguish living cells from dead cells by these methods. Colony counting methods based on colony formation have been used for the detection of living microbial cells. However, these methods are extremely time-consuming (for example, one day or more is required to obtain the detection results) and, furthermore, require complicated and troublesome procedures.
Likewise, classifiable detection or identification of types or kinds of, for example, microorganisms is very important in the clinical test field and various other wide industrial fields. However, extremely troublesome and long term operations are required in the practice thereof, since the classifiable detection or identification is usually based on colony counting methods using so-called selective media or direct counting methods using micrographs.
On the other hand, the present inventors found a phenomenon that a current is generated when living microbial cells are directly contacted with an electrode and reported an electrochemical cell number counting method in Anal. Chim. Acta. 98, 25 (1978); Appl. Environ. Microbiol., 37, 117 (1979); and Eur. J. Appl. Microbiol. Biotechnol., 10, 125 (1980). However, this method still involves problems in that the accuracy of determination is not sufficient and the determination of types of cells and the distinction of microbial properties are not clarified.